setting for not sending title at all - useful for SPAs

[zsolt-dev]

Currently when coding SPAs, I have to wait for async data to fetch and then wait for title to be pushed via React Helmet and then manually call pageview.

I would like to use this library with urlChangeTracker for future projects without having to deal with all those conditions.

But currently with urlChangeTracker I would get the title from the previous page, which is showing up as duplicate in the Analytics dashboard.

It would be nice to have an disableTitle option, that would be used for SPAs, when no title would be sent, only the url.

It would simplify a lot of things for future projects.